The present invention relates to a coating and developing apparatus for forming resist films on substrates such as semiconductor wafers, LCD substrates (glass substrates used for liquid crystal displays) and developing the substrates after exposure to form a desired pattern thereon and also a pattern forming method for forming a desired pattern with this apparatus.
Photolithographic techniques in process for manufacturing semiconductor devices and LCDs, etc., include the following steps.
Firstly, a substrate such as a semiconductor wafer (called wafer hereinafter) is applied a resist solution thereon to be coated with a resist film. The resist film is exposed to a desired pattern through a photomask. A resist film with the desired pattern is then formed through developing processing. A series of these processing are carried out in a system equipped with a coating and developing apparatus and an exposing apparatus connected to each other.
FIG. 1 is a plan view showing such a known system. A cassette C containing substrates, for example 25 semiconductor wafers W, is transferred into a carrier stage 1 on a carrier station A1. Connected to the carrier station A1 is a processing block A2. Connected further to the processing block A2 is an exposing apparatus A4 via an interface block A3.
Each wafer W contained in the carrier C on the carrier stage 1 is picked up by a loading arm 11 and transferred to a coating unit 13 via a transfer mechanism of a shelf unit 12A, for resist coating. The wafer W is then transferred to a cooling section 15 of a shelf unit 12B by a wafer transfer mechanism 14, as shown in FIG. 2. The wafer W is received by a transfer arm 16 of the interface block A3 and transferred to peripheral exposing apparatus 17 of the interface block A3.
The peripheral exposing apparatus 17 exposes the periphery of the wafer W to remove a resist on the periphery, which may otherwise cause generation of particles in the later processing. The wafer W that has been subjected to peripheral exposure is, for example, once transferred to a buffer cassette 18 of the block A3. The wafer W is then transferred, via the transfer arm 16, onto a loading stage (not shown) on the exposing apparatus A4 for exposure.
The exposed wafer W is transferred by the transfer arm 16 of the interface block A3 to the processing block A2 via a loading section 19 of the shelf unit 12B of the processing block A2. After developed by a developing unit (not shown) provided under coating unit 13, the wafer W is returned to the cassette C by the wafer transfer mechanism 14 and the loading arm 11.
The transfer arm 16 provided on the interface block A3 can move forward/backward and upward/downward, and rotate about a vertical axis, and further move in one horizontal-axis direction along a horizontal rail.
Peripheral exposure for the wafers W formed on which is a very narrow resist pattern in accordance with miniaturized semiconductors will cause temperature increase of, for example, 1xc2x0 C. for the wafers W due to ultraviolet radiation. Moreover, loading the wafers W into the buffer cassette 18 before transfer to the exposing apparatus A4 will cause generation of heat in the tight cassette 18, the wafer temperature being thus hardly decreased because heat is hardly released.
It is a requirement for exposing processing that the wafers W are at a certain temperature set at the exposing apparatus A4. Temperature change outside the set temperature could cause wafer expansion or contraction with low accuracy of alignment in exposure, thus resulting in low pattern-size fidelity.
Recent trends in semiconductor fabrication are higher processing speed for the exposing apparatus A4 and shorter waiting time for the wafers W in the buffer cassette 18. These requirements do not allow sufficient decrease in wafer temperature raised due to peripheral exposure while the wafers W are waiting for exposing processing. This often causes temperature increase for the wafers W while being transferred to the exposing apparatus A4, which results in low yields due to effects of heat generated during exposure and thus causing low productivity.
A purpose of the present invention is to provide a coating and developing apparatus and a pattern forming method for providing stable substrate temperature in exposure processing, thus achieving high yields, high transfer performance and high throughput.
The present invention provides a coating and developing apparatus comprising: a carrier table on which at least one carrier containing a plurality of substrates is set; a processor for applying a resist on each substrate taken out from the carrier set on the carrier table and developing the substrate after being subjected to exposing processing; and an interface section for transferring the resist-coated substrate between the processor and an exposing apparatus for applying the exposing processing to the resist-coated substrate, the interface section including; at least one temperature adjuster for adjusting a temperature of the substrate to an appropriate temperature for the exposing processing before the substrate is transferred to the exposing apparatus; and a transfer mechanism for transferring the substrate among the processor, the temperature adjuster and the exposing apparatus.
Moreover, the present invention provides a coating and developing apparatus comprising: a carrier table on which at least one carrier containing a plurality of substrates is set; a processor for applying a resist on each substrate taken out from the carrier set on the carrier table and developing the substrate after being subjected to exposing processing; and an interface section for transferring the resist-coated substrate between the processor and an exposing apparatus for applying the exposing processing to the resist-coated substrate, the interface section including; a shelf section having a plurality of processing units for containing or processing the substrate; a first transfer mechanism for transferring the substrate between the processor and the exposing apparatus; and a second transfer mechanism for receiving the substrate transferred from the processor by the first transfer mechanism and transferring the received substrate to any of the units of the shelf section.
Moreover, the present invention provides a method of forming a pattern comprising the steps of: applying a resist on a surface of a substrate; adjusting a temperature of the resist-coated substrate to an appropriate temperature for exposing processing; exposing the temperature-adjusted substrate; and developing the exposed substrate to form a resist pattern on the substrate surface.
Furthermore, the present invention provides a method of forming a pattern comprising the steps of: applying a resist on a surface of a substrate; exposing periphery of the resist-coated substrate outside a circuit-forming area thereon; adjusting a temperature of the peripheral-exposed substrate to an appropriate temperature for exposing processing; exposing the temperature-adjusted substrate; and developing the exposed substrate to form a resist pattern on the substrate surface.
Moreover, the present invention provides a method of forming a pattern comprising the steps of: applying a resist on a surface of a substrate; adjusting a temperature of the resist-coated substrate to an appropriate temperature for exposing processing; exposing the temperature-adjusted substrate; exposing periphery of the exposed substrate outside a circuit-forming area thereon; and developing the peripheral-exposed substrate to form a resist pattern on the substrate surface.
Furthermore, the present invention provides a method of forming a resist pattern on a surface of a substrate, for a coating and developing apparatus having a processor for applying a resist on a substrate and developing the substrate after being subjected to exposing processing and an interface section for transferring the substrate between the processor and an exposing apparatus for applying the exposing processing to the substrate, the method comprising the steps of: applying a resist on a surface of a substrate by the processor; transferring the resist-coated substrate from the processor to the interface section by a first transfer mechanism and adjusting a temperature of the resist-coated substrate to an appropriate temperature for the exposing processing in the interface section before the resist-coated substrate is transferred to the exposing apparatus; transferring the temperature-adjusted substrate from the interface section to the exposing apparatus by the first transfer mechanism and exposing the temperature-adjusted substrate by the exposing apparatus; and transferring the exposed substrate from the exposing apparatus to the processor via the interface section by the first transfer mechanism and developing the exposed substrate by the processor to form a resist pattern on the substrate surface.